My brother just converted his 99 em1 to obd1. He had the stock p2t ecu and ran fine. He wanted to convert for tuning I guess. Anyways found a Jdm stock p30 ecu. Bought the 2b harness and now he's getting codes 6 10 and 20. Car runs like a bag. Plugs back in the p2t she purrs. I told him to ditch the p30 but he wants the conversion. Must be a faulty ecu. Any thought? Thanks h-t

 

What codes were thrown with the P2T?

 

Thanks for the reply. No codes what so ever. Stock em1 stock b16a2. Nothing hacked full oem. That's why I'm leaning towards the Jdm p30. Just opened the case no chip no nothing ecu still has the knock board. Could be the obd2b-1 harness? Pins seem fine checked it a few times. As soon as you plug back I. The p2t it runs fine just like it always has.

 

Reset the P30 to see if the codes return.

 

Thanks I'll reset it right now and hope they don't come back. If they do would you suspect a faulty ecu? He's using a brand new jumper harness yonaka I believe is the brand.

 

Reset ecu unplugged both ecu and harness ends of jumper inspected pins everything is tight and straight. Same codes 6 10 and 20. I'm thinking it's the ecu. ECT IAT and ELD codes. Plug back in the p2t and it runs fine no codes scanned just incase no fault codes found. Man this is strange.

 

Not sure if this matters but this is a cdm si-R em1

 

Cdm would not have an ELD, so that may explain one code.

Start your troubleshooting here.

 

Where can I find a pin out for obd2b to obd1 jumper harness? Must have some pins mixed up in the harness. I told him thats what you get for buying eBay garbage.

 

Compare these:

http://www.phearable.net/images/tech...schematics.gif

http://www.phearable.net/images/tech...schematics.gif

 

You didn't understand what Ron said? The canadian si-r does not have an eld. If you went and bought a usdm, jdm ecu than it will look for the eld.

 

Ya i understood want RonJ said. Thanks tho. I'm after the iat and ect codes. Anyways I compared the pin outs and the ect and iat are both in the correct locations on the obd2b female end and obd1 male end. De pinned both ends to inspect and the barbs all seem to be intact.

 

With the conversion harness installed, do one of the 2 wires in the ECT and IAT connectors get voltage? If so, what is the voltage reading compared to without the conversion harness installed?

 

Okay so just checked it. With the P2T installed no conversion harness KOEO I have 2.64V for IAT and 2.21V for ECT. Now with the conversion harness installed and P30 I have 5V for both ECT and IAT.

 

Any thoughts?

 

The P2T is giving low voltage readings while the P30+conversion harness is giving expected voltage readings.

 

I can't figure it out. The cars entirely oem. Never even been lowered. Or a intake. Lol. It runs perfect even passes emissions with the p2t. The problem must lie in the ecu or harness no? Vehicle is also cold at this moment in time he's currently not driving it. Could that be the reason for low voltage readings from the ECT and IAT?

 

The codes are thrown by the P30, but the P2T has the low voltage readings. If you were helping me with the same problem, how would you guide me?

 

Well I guess your right there's not much else to try. The problem must lie in the P30 since the harness checked out ok and known working P2T is being used. I guess that's all I would have given for advice. Thanks RonJ for your time

 

The first thing I thought was that whoever measured the voltages mixed up the P2T and P30 readings. If correct, it would explain the P30 codes. You might want to look into this possibility. A large part of successful troubleshooting is basic logic rather than knowledge.

 

I've triple checked everything just as a piece of mind for myself. Pin 13 and 15 on the p30 with conversion harness is 5v.

 

Test the ECT and IAT ground wire (other wire in each connector) for an open with conversion harness plugged in.

 

You measured voltage at ECU pins D13 and D15. Not sure why. Now measure voltage at the corresponding wires in the ECT and IAT connectors with the P30 plugged in.

 

sorry for the late reply but my brother figured it out while I was away for work. One of his co workers was selling a p28 for 75 bucks with a chip for a b16 so he figured why not give it a shot and used the eBay conversion harness he bought and surprisingly it runs great so he's happy. So looks like it was a faulty ecu after all. Thanks for the help